Making gray iron



Patented June 24, 1924.

PATENT OFFICE.

AUGUSTUS F. MEEHAN.

OF GHATTANOOGA, TENNESSEE.

MAKING GRAY IRON.

No Drawing. Application filed February 8, 1822, Serial No. 535,067. Renewed April 8,1924.

To all whom it may concern.

Be it known that I, AUGUSTUS F. MEE- i-iAN, a citizen of the United States, residing at Chattanooga, in the county of Hamilton and State of Tennessee, have invented new and useful Improvements in Making Gray Iron, of which the. following is a specification.

The principal object of the invention is to produce gray iron castings of superior strength and greater uniformity, but not too hard to be readily and economically machined.

Other objects will appear in connection with the following description.

I have ascertained that gray iron of great strength and uniformity, but not too hard to be readily and economically machined. can

be produced by adding to molten white iron,

a silicide substantially free from iron.

Examples of such a silicide are calcium silicide and magnesium silicide, each of which is a strong reducing agent, readily soluble in the molten white iron, easily workable in practice, and acts to rid the bath of occluded gases, and to precipitate the carbon content of the molten white iron.

I prefer to use calcium silicide,

The silicide is preferably added to .the molten white iron in the ladle, but it may he added to the bath within the furnace with good results.

In thus converting white iron into gray iron by the employment of a silicide substantially free from iron, I am able to very accurately control the graphitization of the re sultant gray iron and obtain a substantially my hand this first day uniform product due to the fact that a silicide free from iron, such as calcium silicide, can be readily obtained of uniform compo-- sition.

By convertin white iron into gray iron by the method escribed I am able to obtain substantial uniformity in the product which is of greater stren h than gray iron produced by other ,met ods, while not too hard to be readily machined.

The character of the gray iron produced by this method can be varied by varying the proportion of the silicide which is added to the molten white iron.

By the term molten white iron I mean molten iron of such a composition that castings formed therefrom will be white in fracture.

What I claim as new and desire to secure by Letters Patentis 1. That improvement in the art of converting white iron into gray iron which consists in adding to molten white iron 2 silicide substantially free -from iron.

2. That improvement in the art of conerting white iron into gray iron which consists in adding to molten white iron a car hon-precipitating silicide substantially free from iron.

That improvement in the art of con- \"erting white iron into gray iron which consists in adding to molten white iron calcium silicide.

In testimony whereof. I have hereunto set of February. 1922.

AUGUSTUS F. MEEHAN. 

